arch/mips/include/asm/checksum.h

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 1995, 96, 97, 98, 99, 2001 by Ralf Baechle
   7  * Copyright (C) 1999 Silicon Graphics, Inc.
   8  * Copyright (C) 2001 Thiemo Seufer.
   9  * Copyright (C) 2002 Maciej W. Rozycki
  10  */
  11 #ifndef _ASM_CHECKSUM_H
  12 #define _ASM_CHECKSUM_H
  13
  14 #include <linux/in6.h>
  15
  16 #include <asm/uaccess.h>
  17
  18 /*
  19  * computes the checksum of a memory block at buff, length len,
  20  * and adds in "sum" (32-bit)
  21  *
  22  * returns a 32-bit number suitable for feeding into itself
  23  * or csum_tcpudp_magic
  24  *
  25  * this function must be called with even lengths, except
  26  * for the last fragment, which may be odd
  27  *
  28  * it's best to have buff aligned on a 32-bit boundary
  29  */
  30 __wsum csum_partial(const void *buff, int len, __wsum sum);
  31
  32 __wsum __csum_partial_copy_user(const void *src, void *dst,
  33                                 int len, __wsum sum, int *err_ptr);
  34
  35 /*
  36  * this is a new version of the above that records errors it finds in *errp,
  37  * but continues and zeros the rest of the buffer.
  38  */
  39 static inline
  40 __wsum csum_partial_copy_from_user(const void __user *src, void *dst, int len,
  41                                    __wsum sum, int *err_ptr)
  42 {
  43         might_fault();
  44         return __csum_partial_copy_user((__force void *)src, dst,
  45                                         len, sum, err_ptr);
  46 }
  47
  48 /*
  49  * Copy and checksum to user
  50  */
  51 #define HAVE_CSUM_COPY_USER
  52 static inline
  53 __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len,
  54                              __wsum sum, int *err_ptr)
  55 {
  56         might_fault();
  57         if (access_ok(VERIFY_WRITE, dst, len))
  58                 return __csum_partial_copy_user(src, (__force void *)dst,
  59                                                 len, sum, err_ptr);
  60         if (len)
  61                 *err_ptr = -EFAULT;
  62
  63         return (__force __wsum)-1; /* invalid checksum */
  64 }
  65
  66 /*
  67  * the same as csum_partial, but copies from user space (but on MIPS
  68  * we have just one address space, so this is identical to the above)
  69  */
  70 __wsum csum_partial_copy_nocheck(const void *src, void *dst,
  71                                        int len, __wsum sum);
  72
  73 /*
  74  *      Fold a partial checksum without adding pseudo headers
  75  */
  76 static inline __sum16 csum_fold(__wsum sum)
  77 {
  78         __asm__(
  79         "       .set    push            # csum_fold\n"
  80         "       .set    noat            \n"
  81         "       sll     $1, %0, 16      \n"
  82         "       addu    %0, $1          \n"
  83         "       sltu    $1, %0, $1      \n"
  84         "       srl     %0, %0, 16      \n"
  85         "       addu    %0, $1          \n"
  86         "       xori    %0, 0xffff      \n"
  87         "       .set    pop"
  88         : "=r" (sum)
  89         : "0" (sum));
  90
  91         return (__force __sum16)sum;
  92 }
  93
  94 /*
  95  *      This is a version of ip_compute_csum() optimized for IP headers,
  96  *      which always checksum on 4 octet boundaries.
  97  *
  98  *      By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
  99  *      Arnt Gulbrandsen.
 100  */
 101 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
 102 {
 103         const unsigned int *word = iph;
 104         const unsigned int *stop = word + ihl;
 105         unsigned int csum;
 106         int carry;
 107
 108         csum = word[0];
 109         csum += word[1];
 110         carry = (csum < word[1]);
 111         csum += carry;
 112
 113         csum += word[2];
 114         carry = (csum < word[2]);
 115         csum += carry;
 116
 117         csum += word[3];
 118         carry = (csum < word[3]);
 119         csum += carry;
 120
 121         word += 4;
 122         do {
 123                 csum += *word;
 124                 carry = (csum < *word);
 125                 csum += carry;
 126                 word++;
 127         } while (word != stop);
 128
 129         return csum_fold(csum);
 130 }
 131
 132 static inline __wsum csum_tcpudp_nofold(__be32 saddr,
 133         __be32 daddr, unsigned short len, unsigned short proto,
 134         __wsum sum)
 135 {
 136         __asm__(
 137         "       .set    push            # csum_tcpudp_nofold\n"
 138         "       .set    noat            \n"
 139 #ifdef CONFIG_32BIT
 140         "       addu    %0, %2          \n"
 141         "       sltu    $1, %0, %2      \n"
 142         "       addu    %0, $1          \n"
 143
 144         "       addu    %0, %3          \n"
 145         "       sltu    $1, %0, %3      \n"
 146         "       addu    %0, $1          \n"
 147
 148         "       addu    %0, %4          \n"
 149         "       sltu    $1, %0, %4      \n"
 150         "       addu    %0, $1          \n"
 151 #endif
 152 #ifdef CONFIG_64BIT
 153         "       daddu   %0, %2          \n"
 154         "       daddu   %0, %3          \n"
 155         "       daddu   %0, %4          \n"
 156         "       dsll32  $1, %0, 0       \n"
 157         "       daddu   %0, $1          \n"
 158         "       dsra32  %0, %0, 0       \n"
 159 #endif
 160         "       .set    pop"
 161         : "=r" (sum)
 162         : "0" ((__force unsigned long)daddr),
 163           "r" ((__force unsigned long)saddr),
 164 #ifdef __MIPSEL__
 165           "r" ((proto + len) << 8),
 166 #else
 167           "r" (proto + len),
 168 #endif
 169           "r" ((__force unsigned long)sum));
 170
 171         return sum;
 172 }
 173
 174 /*
 175  * computes the checksum of the TCP/UDP pseudo-header
 176  * returns a 16-bit checksum, already complemented
 177  */
 178 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
 179                                                    unsigned short len,
 180                                                    unsigned short proto,
 181                                                    __wsum sum)
 182 {
 183         return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
 184 }
 185
 186 /*
 187  * this routine is used for miscellaneous IP-like checksums, mainly
 188  * in icmp.c
 189  */
 190 static inline __sum16 ip_compute_csum(const void *buff, int len)
 191 {
 192         return csum_fold(csum_partial(buff, len, 0));
 193 }
 194
 195 #define _HAVE_ARCH_IPV6_CSUM
 196 static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 197                                           const struct in6_addr *daddr,
 198                                           __u32 len, unsigned short proto,
 199                                           __wsum sum)
 200 {
 201         __asm__(
 202         "       .set    push            # csum_ipv6_magic\n"
 203         "       .set    noreorder       \n"
 204         "       .set    noat            \n"
 205         "       addu    %0, %5          # proto (long in network byte order)\n"
 206         "       sltu    $1, %0, %5      \n"
 207         "       addu    %0, $1          \n"
 208
 209         "       addu    %0, %6          # csum\n"
 210         "       sltu    $1, %0, %6      \n"
 211         "       lw      %1, 0(%2)       # four words source address\n"
 212         "       addu    %0, $1          \n"
 213         "       addu    %0, %1          \n"
 214         "       sltu    $1, %0, %1      \n"
 215
 216         "       lw      %1, 4(%2)       \n"
 217         "       addu    %0, $1          \n"
 218         "       addu    %0, %1          \n"
 219         "       sltu    $1, %0, %1      \n"
 220
 221         "       lw      %1, 8(%2)       \n"
 222         "       addu    %0, $1          \n"
 223         "       addu    %0, %1          \n"
 224         "       sltu    $1, %0, %1      \n"
 225
 226         "       lw      %1, 12(%2)      \n"
 227         "       addu    %0, $1          \n"
 228         "       addu    %0, %1          \n"
 229         "       sltu    $1, %0, %1      \n"
 230
 231         "       lw      %1, 0(%3)       \n"
 232         "       addu    %0, $1          \n"
 233         "       addu    %0, %1          \n"
 234         "       sltu    $1, %0, %1      \n"
 235
 236         "       lw      %1, 4(%3)       \n"
 237         "       addu    %0, $1          \n"
 238         "       addu    %0, %1          \n"
 239         "       sltu    $1, %0, %1      \n"
 240
 241         "       lw      %1, 8(%3)       \n"
 242         "       addu    %0, $1          \n"
 243         "       addu    %0, %1          \n"
 244         "       sltu    $1, %0, %1      \n"
 245
 246         "       lw      %1, 12(%3)      \n"
 247         "       addu    %0, $1          \n"
 248         "       addu    %0, %1          \n"
 249         "       sltu    $1, %0, %1      \n"
 250
 251         "       addu    %0, $1          # Add final carry\n"
 252         "       .set    pop"
 253         : "=r" (sum), "=r" (proto)
 254         : "r" (saddr), "r" (daddr),
 255           "0" (htonl(len)), "1" (htonl(proto)), "r" (sum));
 256
 257         return csum_fold(sum);
 258 }
 259
 260 #endif /* _ASM_CHECKSUM_H */